WASHINGTON (CNN) -- President Bush opened his second term Thursday with a promise to the people of the United States and the world -- vowing to promote democracy both at home and abroad.

"It is the policy of the United States to seek and support the growth of democratic movements and institutions in every nation and culture, with the ultimate goal of ending tyranny in our world," Bush said in his inaugural address after his swearing-in ceremony.

In a reference to the September 11, 2001, attacks, Bush told the crowd gathered on the steps of the Capitol that the United States learned on "a day of fire" that protecting the country's borders was no longer enough.

"We have seen our vulnerability, and we have seen its deepest source," he said. "For as long as whole regions of the world simmer in resentment and tyranny -- prone to ideologies that feed hatred and excuse murder -- violence will gather, and multiply in destructive power, and cross the most defended borders, and raise a mortal threat."

Bush said that his primary responsibility was to protect the nation from attack and that "the force of human freedom" was the greatest weapon against tyranny and hatred.

"We are led, by events and common sense, to one conclusion: The survival of liberty in our land increasingly depends on the success of liberty in other lands. The best hope for peace in our world is the expansion of freedom in all the world.

"America's vital interests and our deepest beliefs are now one."

Bush said that the ideals of human freedom and dignity and the quest for self-government for every man and woman helped lead to the creation of the United States.

'The calling of our time'

Bush called the quest for freedom "the urgent requirement of our nation's security, and the calling of our time."

However, he said, the United States would not impose its style of government on other countries.

"Our goal instead is to help others find their own voice, attain their own freedom and make their own way," he said.

The president pledged to continue efforts to spread democracy throughout the world. "We will persistently clarify the choice before every ruler and every nation -- the moral choice between oppression, which is always wrong, and freedom, which is eternally right.

"America will not pretend that jailed dissidents prefer their chains, or that women welcome humiliation and servitude, or that any human being aspires to live at the mercy of bullies.

"... In the long run, there is no justice without freedom, and there can be no human rights without human liberty."

He said that the United States would support the oppressed and that "liberty will come to those who love it."

"When you stand for your liberty, we will stand with you. Democratic reformers facing repression, prison or exile can know: America sees you for who you are -- the future leaders of your free country," Bush said.

A revealing speech

David Gergen, a former adviser to Presidents Nixon, Ford, Reagan and Clinton, said that Bush's speech was straightforward and may not be remembered for its rhetoric, but he stressed that it was an important address.

"[It's] historically significant because I think he's revealed to us today his strategy to win the war on terrorism is far more ambitious than we ever imagined," Gergen said. "It's not simply going after Iraq and getting rid of Saddam [Hussein], nor is it simply going after al Qaeda. It is rather to expand and extend liberty across much of the world.

"No other American president has ever committed himself in an inaugural as fully as this to that kind of aggressive, foreign policy."

Former White House spokesman Ari Fleischer, who served in Bush's first term, said that the president's words would bring hope to people around the world.

"I think again the core of what the president said wasn't that America will do this for you or America will do this or even that this is a speech aimed a foreign leader or foreign government," Fleischer said.

"It was just to the people of these countries where the president talked about. He addressed foreign leaders and said to serve your people you must learn to trust them."

Work to do at home

Although Bush never specifically mentioned Iraq, he said, "Our country has accepted obligations that are difficult to fulfill, and would be dishonorable to abandon. Yet because we have acted in the great liberating tradition of this nation, tens of millions have achieved their freedom."

Through U.S. efforts, "we have lit a fire ... it warms those who feel its power, it burns those who fight its progress, and one day this untamed fire of freedom will reach the darkest corners of our world."

Still, Bush said, the United States has a job to do at home as well -- "the unfinished work of American freedom," showing the world what liberty really means, and changing to meet "the needs of our time."

"To give every American a stake in the promise and future of our country, we will bring the highest standards to our schools, and build an ownership society," he said. "We will widen the ownership of homes and businesses, retirement savings and health insurance -- preparing our people for the challenges of life in a free society."

Character, he said, is built in families, supported by communities "and sustained in our national life by the truths of Sinai, the Sermon on the Mount, the words of the Koran and the varied faiths of our people."

He called for Americans to "look after a neighbor and surround the lost with love," and to abandon racism and bigotry.

"We have known divisions, which must be healed to move forward in great purposes -- and I will strive in good faith to heal them," Bush said. "Yet those divisions do not define America. We felt the unity and fellowship of our nation when freedom came under attack, and our response came like a single hand over a single heart. ...

"When the Declaration of Independence was first read in public and the Liberty Bell was sounded in celebration, a witness said, 'It rang as if it meant something,' " Bush said. "In our time, it means something still.

"America, in this young century, proclaims liberty throughout all the world, and to all the inhabitants thereof. Renewed in our strength -- tested, but not weary -- we are ready for the greatest achievements in the history of freedom."